Type I Construction

[Greg1707]

I did some work in a 12 story condo building. The building was constructed in the 1970s. I was surprised to see that all of the wiring, including feeders and branch circuits, were non metallic. I had expected to see MC cable.
Any insights on this? I have always assumed that structures of this type would not allow NM.

 

[GoldDigger]

I did some work in a 12 story condo building. The building was constructed in the 1970s. I was surprised to see that all of the wiring, including feeders and branch circuits, were non metallic. I had expected to see MC cable.
Any insights on this? I have always assumed that structures of this type would not allow NM.

Even though the building construction is Type I, non metallic wiring methods may not be prohibited if the use of the building does not require that the construction be Type I (or other inherently non-flammable Type)
This is a subtle point, but IMHO very clear in the wording of the code section.
Not all members and not all AHJs agree with this clear interpretation.

The underlying question of what types of construction are allowed for a 12 story condo will have to be answered by local building and fire codes, not by the NEC.

It is also possible that it was a code violation at the time of construction, but was simply overlooked.

 

[don_resqcapt19]

The permission to use NM in buildings exceeding 3 stories was not in the code until the 2002 code as I recall.